The present invention relates in general to fireplace grate devices for wood or coal fuel or solid fuel of similar form, and the like and having means for enhancing transfer of heat from the burning fuel to the air in the room or living space served by the fireplace, and more particularly to a forced-air, heat-exchanging fireplace grate structure having a plurality of generally U-shaped or C-shaped hollow tubes arranged in vertical planes forming a supporting cradle for the wood or coal fuel and having a pressurized plenum and motorized fan system for achieving forced air convection of air through the tubes in close heat exchange relationship with the heat of the burning fuel.
A number of fireplace grate type structures have been devised for supporting burning fuel such as wood, coal or other solid fuel and having air conveying tubes formed by the grate members for receiving air from the room to be served by the fireplace grate structure, passing the air through the tubes in good heat exchange relation with the burning fuel, and discharging the air back into the room to enhance the heating efficiency. Typical of these are prior U.S. Pat. Nos. 1,030,002 to Livingston, 1,313,085 to Greene, 1,608,745 to Holbek, and 1,747,259 to Pierce, all of which employ a plurality of hollow tubular members arranged in a generally L-shaped configuration having a lower leg provided with an air inlet to receive air from the room and conduct the same rearwardly, and then upwardly and forwardly about the burning fuel to achieve better heating of the air, and then discharge the heated air back into the living space. These devices all, however, merely rely upon convention currents produced by the heating of the air in the tubular members to draw room air into the lower legs of the tubular members and achieve air circulation movement rearwardly, upwardly and forewardly through the members to discharge back into the room. No pressurized plenum or motor driven fan for achieving forced circulation of room air through the tubes of such devices is proposed in any of these patents.
Horizontally arranged tubular log or solid fuel supporting structures have been proposed, in conjunction with motor driven fans for circulating the air through some kind of underlying tubular duct structure located wholly at the bottom of a fireplace. However, these devices do not effect a pressurized supply of appropriately distributed pressurized air from a pressurized plenum or manifold to a plurality of vertical substantially C-shaped or U-shaped air heating and discharging tubes.
An object of the present invention is the provision of a fireplace grate device formed of a plurality of vertically arranged hollow air conveying and heating tubes curved in a forewardly facing concave pattern to define a cradle for logs or other fuels, for use with existing fireplaces which will not alter the fireplace structure and yet will significantly enhance the heating efficiency of the fireplace.
Another object of the present invention is the provision of a novel fireplace grate structure of the type described in the proceeding paragraph, wherein a pressurized manifold and associated motor driven fan is incorporated in the fireplace grate unit and communicates with air inlet openings at the lower ends of the tubes to properly distribute pressurized air to the lower inlets of the tubes to be heated during passage through the tubes and discharged in desired directions back into the room to be heated, eliminating the need for any motorized air supply systems located externally of the fireplace and connected to the grate structure.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken into conjunction with the accompanying drawings illustrating preferred embodiments of the invention.